It is known to equip a host-vehicle with a radar-system for detecting objects such as other-vehicles proximate to the host-vehicle. Such object detection is desirable for detecting, for example, other-vehicles in the so called blind-spot which is not readily observable by an operator of a host-vehicle using typical side-view and rear-view mirrors, and for detecting a trailer towed by the host-vehicle. Such object detection may also be useful to warn the operator of a rapidly approaching vehicle in an adjacent lane if the operator indicates that a lane-change is about to be executed by, for example, activating a turn-signal indicator, or for detecting objects behind the host-vehicle when backing-up. If the host-vehicle is towing a trailer, reflections of radar-signals by the trailer may interfere with the detection of a target that does not correspond to or is not associated with the trailer. In addition, when the host-vehicle is turning, the trailer may cause the warning-system to activate and give a false indication of another object or vehicle proximate to the host-vehicle, as the trailer detection zone only applies to the area directly behind the host-vehicle.